Pediatric Examination and Board Review (29 page)

Acute chest syndrome or pneumonia associated with pleural effusion may be a first-time presentation for an African American child with sickle cell disease. It would be important to take a history for sickle cell disease and validate the child’s hemoglobin type by Sickledex or hemoglobin electrophoresis. Immunodeficiencies both congenital and acquired tend to present earlier than 16 months of age but should be considered as well.

10.
(C)
In this case, after the removal of the pleural fluid, a 2-cm lung abscess is apparent. The lower respiratory tract infection illustrated by this child occurs most often after initial colonization of the nasopharynx with the offending organism followed by aspiration or inhalation. Disease commonly occurs when a host is colonized with a new bacterium. Of the pathogens listed, the most likely cause is
S aureus,
although
S pneumoniae
is the most common cause of bacterial pneumonia. Frequent oral aspiration often occurs in debilitated children, and anaerobic constituents of the upper airway flora should be considered as causes in these patients as well.

Associated bacteremia is present in 10-20% of cases of bacterial pneumonia/empyema. If the child can produce sputum, it may be a useful tool to identify the responsible organism. However, in children younger than about 9 years of age, expectoration of sputum rarely occurs, and pediatricians rely on culture of the pleural fluid and the blood for a “certain” microbiologic diagnosis of pneumonia.

11.
(A)
The 2 most common organisms causing neonatal infection including bacteremia and pneumonia are group B streptococcus and
E coli
. Infections caused by other streptococcal species and
S aureus
have been reported but are less common.

12.
(C)
The abrupt onset of severe symptoms such as fever, anorexia, and tachypnea should lead the clinician to suspect a bacterial pathogen. The most common cause of bacterial pneumonia remains
S pneumoniae
. This species is also associated with parapneumonic effusions, which are sometimes complicated. At this age, additional bacterial causes of pneumonia with effusion should also be considered such as
S aureus
. In the vaccine era,
H influenzae
has been a rare cause. There are also a variety of less frequent causative organisms. Common causes of pneumonia that are rarely associated with pleural effusion include
M pneumoniae
and
C trachomatis
, the latter in young infants. Viral agents, particularly influenza, parainfluenza, RSV, and adenovirus, are also common causes of lower respiratory tract infection. Influenza, parainfluenza, and adenovirus may cause a high fever and all may result in a toxicappearing child, but these viruses rarely produce a pleural effusion.

13.
(B)
Pleural effusions in children occur for reasons other than complicated bacterial pneumonia. These effusions are associated with chest trauma, cardiac surgery, and congestive heart failure. The hemopneumothorax that occurs after chest trauma is obvious by history and by examination of the aspirated fluid. A transudate is commonly found in the patient with cardiac failure or following cardiac surgery and has the characteristics previously described. A chylothorax may follow trauma or thoracic surgery. It is characterized by a marked elevation in the pleural fluid triglyceride concentration that reflects injury to the lymphatic system. The pH, protein, and glucose are similar to the values found in serum.

14.
(D)
A pleural effusion in the child with a malignancy can be a transudate or an exudate but contains abnormal or atypical white cells suggestive of a malignancy. Notably, in malignant effusion, the glucose concentration can be as low as encountered in empyema.

15.
(D)
Malignant pleural effusion is substantially more common in the adult population. When a malignant effusion develops in a child, it is most often associated with a thoracic lymphoma.

S
UGGESTED
R
EADING

Heffner JE, Brown LK, Barbieri C, et al. Pleural fluid chemical analysis in parapneumonic effusions.
Am J Respir Crit Care Med.
1995;151:1700-1708.

Miller MA, Ben-Ami T, Daum RS. Bacterial pneumonia in neonates and older children. In: Taussig LM, Landau LI, eds.
Pediatric Respiratory Medicine
. St. Louis, MO: Mosby; 1999:644-647.

Pistolesi M, Miniati M, Giuntini C. Pleural liquid and solute exchange.
Am Rev Respir Dis.
1989;140:825-847..

Sahn SA. Management of complicated parapneumonic effusions.
Am Rev Respir Dis.
1993;148:813-817.

CASE 15: AN 8-MONTH-OLD WITH GENERALIZED SEIZURES

An 8-month-old male infant is brought to the emergency department by his grandmother after he began having jerking movements of his arms and legs that started approximately 20 minutes before presentation to the hospital. The nurse reports that in triage the infant had intermittent jerking of his arms and legs and seemed sleepy. The history is uninformative. His grandmother reports that she has been feeding him only formula over the last 5 days. She has been caring for him while his mother is out of town. Review of symptoms is negative for upper respiratory tract illness, fever, vomiting, diarrhea, or change in eating habits.

On physical examination, the vital signs are normal. He has no obvious jerking movements, but he has diminished muscle tone. His pupils are 3 mm and respond sluggishly to light bilaterally. The anterior fontanel is soft. His cardiorespiratory examination is normal.

SELECT THE ONE BEST ANSWER

1.
If the child begins to have generalized seizures in the emergency department, the first intervention must be

(A) administration of phenobarbital

(B) ensure a patent airway

(C) obtain an immediate CT scan of the head, with and without contrast

(D) give 10 mL/kg 50% glucose

(E) none of the above

2.
Among the following, the first screening tests that need to be performed are

(A) serum glucose and electrolytes

(B) a CBC and differential

(C) an erythrocyte sedimentation rate and CRP

(D) examination of CSF

(E) CT scan

3.
The patient continues to have generalized seizures even after administration of IV lorazepam at a dose of 0.3 mg/kg when the electrolytes are proven normal except for a serum sodium of 118 mEq/L. The intervention required is

(A) IV phenytoin, 5 mg/kg

(B) IV 3% NaCl, 2 mEq/kg

(C) IV phenobarbital, 10 mg/kg

(D) IV normal saline, 2 mEq/kg

(E) IV 10% dextrose, 4 mL/kg

4.
Additional history regarding which of the following items would most help to explain why this child had seizures

(A) the manner in which the grandmother is preparing food for the child

(B) the drugs available in the grandmother’s house for accidental ingestion

(C) the family history of seizures

(D) recent use of corticosteroids in the child

(E) none of the above

5.
The child’s disposition after the seizures are controlled in the emergency department should be which of the following

(A) the child can now be safely discharged with close follow-up

(B) the child should be referred to an endocrinologist

(C) the child needs to have a genetics workup for adrenal disorders

(D) the child should be admitted to the hospital and have careful monitoring of his serum sodium

(E) B and C

6.
If trying to distinguish symptoms of inappropriate antidiuretic hormone (SIADH) from water intoxication, urine electrolytes would be

(A) not useful

(B) likely to show a urine sodium concentration less than 20 mEq/L if water intoxication is to blame

(C) likely to show excessive sodium excretion if SIADH is to blame

(D) likely to show low urine osmolality if SIADH is to blame

(E) likely to show no abnormalities if water intoxication is to blame

7.
The optimal time frame to correct the serum sodium to a normal range after the seizures are controlled in the emergency department is

(A) as soon as possible

(B) 6 hours

(C) 24 hours

(D) 72 hours

(E) 4-5 days

8.
The complication to be most feared from quickly increasing a patient’s serum sodium is

(A) intracranial hemorrhage

(B) hydrocephalus

(C) pontine demyelination

(D) occipital blindness

(E) stroke

9.
Complications from a too rapid correction of serum sodium, most often, are observed in which of the following populations?

(A) young infants

(B) preschool children

(C) school-age girls

(D) young adult women

(E) teenage boys

10.
The differential diagnosis of hyponatremia includes all of the following except